1. Field of the Invention
This invention relates generally to roof structures and more particularly to an improved relatively light weight, low cost roof structure of the class disclosed in my prior U.S. Pat. No. 4,676,034 and to an improved support structure for the roof material.
2. Discussion of the Prior Art
Roof structures of the class to which this invention pertains are primarily intended for applications which require relatively large floor area coverage, such as commercial greenhouses, swimming pool enclosures and the like. The prior art is replete, of course, with a vast assortment such roof structures. One example of a roof structure of this kind is disclosed in U.S. Pat. No. 3,488,899. This patented roof structure, however, is relatively heavy, costly to construct, and presents the condensate problem discussed below. My prior U.S. Pat. No. 4,676,034 discloses an improved roof structure which overcomes these disadvantages.
My prior patented roof structure includes a roof proper constructed of a relatively thin, light weight, sheet-like roofing material and a relatively light weight frame below and supporting the roof. The roof supporting frame includes a plurality of long slender lower frame members which are supported in spaced parallel relation on upstanding posts, walls or the like and long slender upper frame members which extend transverse to and are supported on and rigidly joined to the lower frame members with the upper members disposed in spaced parallel relation along the lower members. The roofing material overlies and is directly supported on these upper frame members. For reasons of strength, rain runoff, and appearance, the roof is supported in such a way that it slopes. The particular roof structure illustrated in my prior patent, for example, is an arched roof structure having a roof proper composed of fiberglass panels and a roof supporting frame which supports the roof in an arch-like configuration, such that the roof has a central crest and two arcuate portions which extend with a downward slope in opposite directions from the crest to lower roof edges .
A roof structure of this type presents the problem that condensate tends to form on the under side of the roof, that is on the bottom surface of the sheet-like roofing material and run downwardly toward the lower roof edges. Gutters are placed along these lower edges to collect and carry off the condensate. One disadvantage of the roof structure disclosed in U.S. Pat. No. 3,488,899 resides in the fact that the condensate collection system is somewhat ineffective with the result that condensate tends to drip into the space below the roof.
My prior U.S. Pat. No. 4,676,034 solves this condensate drip problem in the following way. The lower frame members of the roof supporting frame extend parallel to the direction in which condensate tends to run downwardly along the underside of the roof and contain in their upper sides a longitudinal, upwardly opening channel referred to herein as a condensate drainage channel. The upper frame members extend transverse to the lower frame members and hence also transverse to said direction in which condensate tends to run downwardly along the underside of the roof. The upper sides of these upper frame members contain longitudinal channels, referred to herein as condensate collection channels, which open upwardly toward and are disposed in condensate collecting relation to the underside of the roof, such that condensate running downwardly along the underside enters these collection channels. Condensate is conducted from the condensate collection channels to the condensate drainage channels by wires which extend between and along which condensate flows from the collection channels to the drainage channels. The condensate then flows downwardly thru the drainage channels to gutters at the lower ends of the latter channels.
When properly constructed, this condensate collection system of my prior patent is very effective from the standpoint of its ability to collect and dispose of the condensate which tends to form on the underside of the roof and thereby prevent dripping of the condensate into the underlying space below the roof. The collection system, however, has one disadvantage which this invention overcomes. This disadvantage resides in the fact that workmen installing my patented roof structure often forget to or improperly install the condensate conducting wires between the collection and drainage channels. This reduces the effectiveness of the condensate collection system and causes dripping of condensate into the underlying space in direct proportion to the number of condensate collection wires which are omitted or improperly installed.